This invention relates to manually operated devices for assisting in loosening and tightening fasteners. The fasteners utilized in conjunction with the device are screws, nuts, bolts, and the like.
Until the present invention, the loosening or tightening of fasteners required the application of force to the fastener either by hand, with a screwdriver or wrench, or by means of a power device. Standard power devices most commonly make use of electrical, pneumatic or hydraulic power sources.
One of the drawbacks of such tools as actually used with fasteners exhibits itself when the fastener is either difficult to loosen or difficult to tighten. In these cases, the individual using the hand tool either tends to or is required to apply extreme force to the fastener by way of the tool. Many times this force results in damage to the fastener, as with scarred screwheads or rounded corners on a bolthead, damage to the workpiece if the tool slips from the fastener, or damage to the tool itself.
The power tools present a different problem in that they are generally made for use with larger fasteners and are so manufactured that a large amount of energy is applied to the fastener. These power tools are, therefore, generally inappropriate for use with small fasteners or fasteners contained in small or delicate workpieces.
With both hand-held and power driven tools, it is a common practice to apply to the fasteners not just the torque that is required to loosen or tighten the fastener, but in addition, to apply an axially-directed thrust force. For many applications such a thrust force is undesirable and should be avoided completely.